diff --git a/bdo.cabal b/bdo.cabal
--- a/bdo.cabal
+++ b/bdo.cabal
@@ -1,5 +1,5 @@
 name:                bdo
-version:             0.1.0.0
+version:             1.0.0
 synopsis:            Update CSS in the browser without reloading the page.
 description:         Update CSS in the browser without reloading the page.
 license:             BSD3
@@ -11,8 +11,16 @@
 cabal-version:       >=1.8
 data-files: bdo.js
 
+library
+  exposed-modules:  Bdo
+  other-modules:    Http
+  build-depends:    base >= 4 && < 5,
+                    url, text, network, aeson
+  hs-source-dirs:   src
+
 executable bdo
   main-is:          Main.hs
+  other-modules:    Bdo, Http
   build-depends:    base >= 4 && < 5,
                     url, text, network, aeson
-  hs-source-dirs: src
+  hs-source-dirs:   src
diff --git a/src/Bdo.hs b/src/Bdo.hs
new file mode 100644
--- /dev/null
+++ b/src/Bdo.hs
@@ -0,0 +1,144 @@
+{-# LANGUAGE ViewPatterns #-}
+{-# LANGUAGE OverloadedStrings #-}
+
+-- | Accepts polling requests and such.
+
+module Bdo
+  (startServer)
+  where
+
+import           Control.Concurrent
+import           Control.Exception
+import           Control.Monad
+import           Data.Aeson
+import           Data.List
+import           Data.Maybe
+import           Data.Monoid
+import           Data.Text.Lazy (Text)
+import qualified Data.Text.Lazy as T
+import qualified Data.Text.Lazy.IO as T
+import           Http
+import           Network
+import           Network.URL
+import           Paths_bdo
+import           Prelude hiding (catch)
+import           System.Environment
+import           System.IO
+
+startServer :: Int -> IO ()
+startServer listenPort = do
+  clients <- newMVar []
+  listener <- listenOn (PortNumber (fromIntegral listenPort))
+  currentClient <- newMVar Nothing
+  let printCurrentClient h = do
+         cur <- readMVar currentClient
+         case cur of
+           Nothing -> T.hPutStrLn h "No current client"
+           Just (client,link) -> T.hPutStrLn h $ "Current client is: " <> client <> ", updating link: " <> link
+      update h client link = do
+        clients <- readMVar clients
+        case lookup client clients of
+          Nothing -> T.hPutStrLn h "Unknown client. To see list of clients: clients"
+          Just (links,Just h')
+            | link `elem` links -> do T.hPutStrLn h "Sending link update ..."
+                                      reply h' [] link
+                                      hClose h'
+            | otherwise -> T.hPutStrLn h "That link doesn't exist in the page. To see the page's links: clients"
+          _ -> T.hPutStrLn h "That client isn't connected right now."
+      updateCurrentClient h = do client <- readMVar currentClient
+                                 case client of
+                                   Nothing -> hPutStrLn h "No current client!"
+                                   Just (client,link) -> update h client link
+      printClients h = do clients <- readMVar clients
+                          mapM_ (\(referer,(links,_)) -> do
+                           T.hPutStrLn h (referer <> ":\n" <>
+                                          T.intercalate "\n" (map ("  "<>) links) <>
+                                          "\n"))
+                            clients
+                          printCurrentClient h
+      setClient h client link = do
+        clients <- readMVar clients
+        case lookup client clients of
+          Nothing -> T.hPutStrLn h "No such client"
+          Just{} -> do modifyMVar_ currentClient (const (return (Just (client,link))))
+                       printCurrentClient h
+  void $ forkIO $ flip finally (sClose listener) $ forever $ do
+    (h,_,_) <- accept listener
+    let closing m = finally m (hClose h)
+    forkIO $ do
+      hSetBuffering h NoBuffering
+      headers <- getHeaders h
+      case headers of
+        ["update"] -> closing (updateCurrentClient h)
+        [T.words -> ["update",client,link]] -> update h client link
+        ["clients"] -> closing $ printClients h
+        [T.words -> ["set",client,link]] -> closing $ setClient h client link
+        [T.words -> [(importURL . T.unpack) -> Just client,(importURL . T.unpack) -> Just link]] -> closing $ do
+         T.putStrLn "Updating from socket request."
+         update h (T.pack (exportURL client))
+                  (T.pack (exportURL link))
+        _ -> do
+         case requestMethod headers of
+           Just (method,url) -> dispatch h clients method url headers
+           _ -> closing $ T.putStrLn $ "Request ignored: " <> T.pack (show headers)
+
+  forever $ do
+    line <- T.getLine
+    case T.words line of
+      ["clients"] -> printClients stdout
+      ["update",client,link] -> update stdout client link
+      ["update"] -> updateCurrentClient stdout
+      ["set",client,link] -> setClient stdout client link
+      _ -> T.putStrLn $ "Unknown command. Commands: clients, update <client> <stylesheet>, set <client> <stylesheet> (sets the current client/stylesheet), update (no args, uses current client)"
+
+dispatch :: Handle -> MVar [(Text,([Text],Maybe Handle))] -> Text -> URL -> [Text] -> IO ()
+dispatch h cs method url headers = do
+  logLn $ T.pack (show h) <> ": Client connected."
+  go [("bdo",bdo)
+     ,("links",links)
+     ,("poll",poll)]
+
+  where bdo = do
+          getJs (fromMaybe "localhost" (lookupHeader "host" headers)) >>= replyJs h
+          hClose h
+
+        poll = modifyClient (\(links,_) -> (links,Just h))
+
+        links = do
+          rest <- T.hGetContents h
+          case requestBody headers rest of
+            Nothing -> return ()
+            Just body -> case parsePost body of
+              Nothing -> return ()
+              Just params -> case lookup "links" params of
+                Nothing -> return ()
+                Just links -> do modifyClient (\(_links,handle) -> (T.lines links,handle))
+                                 logLn $ T.pack (show h) <> ": Links updated."
+                                 reply h [] "Links updated."
+          hClose h
+
+        go handlers =
+          case find ((`isPrefixOf` (url_path url)).fst) handlers of
+              Just (_,handle) -> handle
+              Nothing -> do
+                logLn $ T.pack (show h) <> ": Unhandled request: " <> T.pack (show url)
+                hClose h
+        referer = fromMaybe "any" $ lookupHeader "referer" headers
+        modifyClient f = modifyMVar_ cs (return . modify) where
+          modify xs = case lookup referer xs of
+                        Nothing -> (referer,f (mempty,Nothing)) : xs
+                        Just x -> (referer,f x) : filter ((/=referer).fst) xs
+
+logLn :: Text -> IO ()
+logLn = T.hPutStrLn stderr
+
+getJs :: Text -> IO Text
+getJs host = do
+  js <- getDataFileName "bdo.js" >>= T.readFile
+  return $
+    T.unlines [js
+              ,"bdo.host = " <> T.pack (show ("http://" <> host <> "/" :: Text)) <> ";"
+              ,"bdo.init();"
+              ]
+
+replyJs h = reply h [("Content-Type","text/javascript; charset=utf-8")]
diff --git a/src/Http.hs b/src/Http.hs
new file mode 100644
--- /dev/null
+++ b/src/Http.hs
@@ -0,0 +1,68 @@
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE ViewPatterns #-}
+{-# LANGUAGE OverloadedStrings #-}
+
+-- | HTTP utilities.
+
+module Http where
+
+import           Control.Arrow
+import           Control.Exception
+import           Control.Monad
+import           Data.Char
+import           Data.List
+import           Data.Maybe
+import           Data.Monoid
+import           Data.Text.Lazy (Text)
+import qualified Data.Text.Lazy as T
+import qualified Data.Text.Lazy.IO as T
+import           Network.URL
+import           Numeric
+import           Prelude hiding (catch)
+import           System.IO
+
+-- | Parse a POST request's parameters.
+parsePost :: Text -> Maybe [(Text,Text)]
+parsePost body = fmap (map (T.pack *** T.pack) . url_params)
+                      (importURL ("http://x/x?" ++ T.unpack body))
+
+-- | Get the request method.
+requestMethod :: [Text] -> Maybe (Text,URL)
+requestMethod headers =
+   case T.words (T.concat (take 1 headers)) of
+     [method,(importURL . T.unpack) -> Just url,_] ->
+       return (method,url)
+     _ -> Nothing
+
+-- | Get the request body.
+requestBody :: [Text] -> Text -> Maybe Text
+requestBody headers body = do
+  len <- lookup "content-length:" (map (T.break (==' ') . T.map toLower) headers)
+  case readDec (T.unpack (T.unwords (T.words len))) of
+    [(l,"")] -> return (T.take l body)
+    _ -> Nothing
+
+-- | Read up to the headers.
+getHeaders :: Handle -> IO [Text]
+getHeaders h = go [] where
+  go ls = do
+    l <- catch (T.hGetLine h)
+               (\(e::IOException) -> return "\r")
+    if l == "\r"
+       then return (reverse ls)
+       else go (T.filter (/='\r') l : ls)
+
+-- | Make a HTTP reply.
+reply :: Handle -> [(Text,Text)] -> Text -> IO ()
+reply h headers body = T.hPutStrLn h resp where
+  resp = T.unlines ["HTTP/1.1 200 OK"
+                   ,"Content-Length: " <> T.pack (show (T.length body))
+                   ,"Access-Control-Allow-Origin: *"
+                   ,T.unlines (map (\(key,value) -> key <> ": " <> value) headers)] <>
+         body
+
+-- | Lookup the given header from the headers list.
+lookupHeader :: Text -> [Text] -> Maybe Text
+lookupHeader key headers =
+  fmap (T.drop 2 . T.dropWhile (/=':'))
+       (lookup key (map (T.break (==':') . T.map toLower) headers))
diff --git a/src/Main.hs b/src/Main.hs
--- a/src/Main.hs
+++ b/src/Main.hs
@@ -1,11 +1,11 @@
 {-# LANGUAGE ViewPatterns #-}
 {-# LANGUAGE OverloadedStrings #-}
 
--- | Main bdo server. Accepts polling requests and such. Possibly the
--- worst code I've ever written. I want a prize.
+-- | Main bdo server.
 
 module Main where
 
+import Bdo
 import           Control.Concurrent
 import           Control.Exception
 import           Control.Monad
@@ -29,118 +29,4 @@
 main = do
   (listenPort:_) <- getArgs
   hSetBuffering stdout NoBuffering
-  clients <- newMVar []
-  listener <- listenOn (PortNumber (fromIntegral (read listenPort :: Int)))
-  currentClient <- newMVar Nothing
-  let printCurrentClient h = do
-         cur <- readMVar currentClient
-         case cur of
-           Nothing -> T.hPutStrLn h "No current client"
-           Just (client,link) -> T.hPutStrLn h $ "Current client is: " <> client <> ", updating link: " <> link
-      update h client link = do
-        clients <- readMVar clients
-        case lookup client clients of
-          Nothing -> T.hPutStrLn h "Unknown client. To see list of clients: clients"
-          Just (links,Just h')
-            | link `elem` links -> do T.hPutStrLn h "Sending link update ..."
-                                      reply h' [] link
-                                      hClose h'
-            | otherwise -> T.hPutStrLn h "That link doesn't exist in the page. To see the page's links: clients"
-          _ -> T.hPutStrLn h "That client isn't connected right now."
-      updateCurrentClient h = do client <- readMVar currentClient
-                                 case client of
-                                   Nothing -> hPutStrLn h "No current client!"
-                                   Just (client,link) -> update h client link
-      printClients h = do clients <- readMVar clients
-                          mapM_ (\(referer,(links,_)) -> do
-                           T.hPutStrLn h (referer <> ":\n" <>
-                                          T.intercalate "\n" (map ("  "<>) links) <>
-                                          "\n"))
-                            clients
-                          printCurrentClient h
-      setClient h client link = do
-        clients <- readMVar clients
-        case lookup client clients of
-          Nothing -> T.hPutStrLn h "No such client"
-          Just{} -> do modifyMVar_ currentClient (const (return (Just (client,link))))
-                       printCurrentClient h
-  void $ forkIO $ flip finally (sClose listener) $ forever $ do
-    (h,_,_) <- accept listener
-    let closing m = finally m (hClose h)
-    forkIO $ do
-      hSetBuffering h NoBuffering
-      headers <- getHeaders h
-      case headers of
-        ["update"] -> closing (updateCurrentClient h)
-        [T.words -> ["update",client,link]] -> update h client link
-        ["clients"] -> closing $ printClients h
-        [T.words -> ["set",client,link]] -> closing $ setClient h client link
-        [T.words -> [(importURL . T.unpack) -> Just client,(importURL . T.unpack) -> Just link]] -> closing $ do
-         T.putStrLn "Updating from socket request."
-         update h (T.pack (exportURL client))
-                  (T.pack (exportURL link))
-        _ -> do
-         case requestMethod headers of
-           Just (method,url) -> dispatch h clients method url headers
-           _ -> closing $ T.putStrLn $ "Request ignored: " <> T.pack (show headers)
-
-  forever $ do
-    line <- T.getLine
-    case T.words line of
-      ["clients"] -> printClients stdout
-      ["update",client,link] -> update stdout client link
-      ["update"] -> updateCurrentClient stdout
-      ["set",client,link] -> setClient stdout client link
-      _ -> T.putStrLn $ "Unknown command. Commands: clients, update <client> <stylesheet>, set <client> <stylesheet> (sets the current client/stylesheet), update (no args, uses current client)"
-
-dispatch :: Handle -> MVar [(Text,([Text],Maybe Handle))] -> Text -> URL -> [Text] -> IO ()
-dispatch h cs method url headers = do
-  logLn $ T.pack (show h) <> ": Client connected."
-  go [("bdo",bdo)
-     ,("links",links)
-     ,("poll",poll)]
-
-  where bdo = do
-          getJs (fromMaybe "localhost" (lookupHeader "host" headers)) >>= replyJs h
-          hClose h
-
-        poll = modifyClient (\(links,_) -> (links,Just h))
-
-        links = do
-          rest <- T.hGetContents h
-          case requestBody headers rest of
-            Nothing -> return ()
-            Just body -> case parsePost body of
-              Nothing -> return ()
-              Just params -> case lookup "links" params of
-                Nothing -> return ()
-                Just links -> do modifyClient (\(_links,handle) -> (T.lines links,handle))
-                                 logLn $ T.pack (show h) <> ": Links updated."
-                                 reply h [] "Links updated."
-          hClose h
-
-        go handlers =
-          case find ((`isPrefixOf` (url_path url)).fst) handlers of
-              Just (_,handle) -> handle
-              Nothing -> do
-                logLn $ T.pack (show h) <> ": Unhandled request: " <> T.pack (show url)
-                hClose h
-        referer = fromMaybe "any" $ lookupHeader "referer" headers
-        modifyClient f = modifyMVar_ cs (return . modify) where
-          modify xs = case lookup referer xs of
-                        Nothing -> (referer,f (mempty,Nothing)) : xs
-                        Just x -> (referer,f x) : filter ((/=referer).fst) xs
-
-logLn :: Text -> IO ()
-logLn = T.hPutStrLn stderr
-
-getJs :: Text -> IO Text
-getJs host = do
-  js <- getDataFileName "bdo.js" >>= T.readFile
-  return $
-    T.unlines [js
-              ,"bdo.host = " <> T.pack (show ("http://" <> host <> "/" :: Text)) <> ";"
-              ,"bdo.init();"
-              ]
-
-replyJs h = reply h [("Content-Type","text/javascript; charset=utf-8")]
+  startServer (read listenPort)